wellington boot

Well it's not quite true that there hasn't been a significant build in member agreement for the pressure rise, because it wasnt really predicted by the gfs at all previously. Your right that the ukmo did previously show an HP edging westwards from our north east, but it was a different evolution and didnt appear to be coming to much. This is much mroe convincing. Each gfs run recently, with few exceptions, has shown the battle lastiung longer and longer. And high pressure to the east , if it can hold off the atlantic for long enough, will begin to fight back. I talked about this a couple of days ago. Battleground situations are among the only ones (if not the only ones) which can change on the models at very short range. Even last yesr, the same happened to some extent, when it looked like the atlantic would steam straight through, but there was a battle which lasted a couple of days in the end. Perhaps we can get it even better this time

You say that it's an outlier, but I would suggest that it's only the result of a devloping trend. Ive been very busy the last couple of days so havent really been posting, but ive been checking the model runs run by run all the same. The main thing i noticed, which i drew attention to recently in fact, was the fact that the high pressure to the east was being progged stronger and stronger, creating a more prolonged battleground situation. This is a trend, and especially if we take into the runs whihc were flying around a few days ago, which showed high pressure to our north and east, like a few of the ensemble runs, and those jma runs, i would not be surprised if the LP was held off and heights increased again to the north and east.

I'm going for an ambitious 3.0. Tempted by 3.4, but Im going to set my sights for cold weather. couple of cold weeks to start, and perhaps another cold blast at the end of the month, with some milder stuff in between.

Remember beng, this winter has not been such a mild one all over the northern hemisphere. I'm not sure how it's been over in iceland, but with the polar vortex over greenland for so long, sweeping icy greenland air over iceland, id have thought it must have been pretty cold over there this winter. Furthermore, observe on the ice coverage map that the different colours represent percentage of the sea frozen, and between greenland and iceland the colour is green, signifying that about 30% of the sea is frozen there. So an ice bridge could take a while

oh and thanks roger for your very interesting post. I look forward to re-reading it tomorrow and taking it in better.

I continue to agree with what you say snowprincess; there is certainly no need to jump to conclusions based on the occurrence of unusually warm winters over the last decade. And this reminds me - I have a few issues with a number of your posts Dawlish, so if you (Dawlish) would like to clarify these I would appreciate it: You tell us that the "one year/18 month trend stuff counts for nothing" and has "no statistical relevance", and then go on to write that you "won't be persuaded by the "well it happened, so it can happen again" argument", shown here: Well firstly, you say you won't be persuaded by the "well it happened, so etc." argument, but in the quote below, you imply that your prediction for the coming winter is entirely based on what has happened in the last few years. So you seem to be saying "well it happened before, in the last few years, so it will probably happen again." I'm not sure that this seems like a very thorough method of approaching a winter forecast. As Snow Princess rightly asserted, "Statistics are vulnerable things - they are there to be knocked down at any time and changed." And continuing on the subject of this post, I believe it is really the last 15 years, since 1990, where any trend has really developed, so I'll assume that you mean that you are basing evidence on the last 15 years or so. Anyhow, you seem to be judging the records and new trends of the last 15 years as statistically significant, unlike those of the last 18 months (a period which accounts for 10% of the last 15 years, incidentally). So is 15 years the exact number of years you have to include in your reckoning in order to be relevant? Why not go back 60 years, in which case, as someone earlier posted, possibly BFTP, you would see opposite trends, certainly for particular, connected factors, such as Arctic temperatures. Surely it's a bit short sighted to draw a line somewhere (perhaps 1990 in this case) and decide that only data collected since then is relevant to your predictions. Anyway, one last thing. This is not terribly important, and I hope you don't think I'm attacking you for the sake of it, but in the following quote you talk about why you think continued warming is likely, and you mention evidence for this - computer models which predict how far the warming trend might go. Thing is, you then say, "I don't actually believe that, but add the computer predictions to my own calculated probability and the argument for continued warming is very persuasive". I would advise against using evidence you don't believe to back up your argument, and saying that it contributes to your conviction...

It's gonna be 10.8. It's a fact

Thanks Steve. That was the most informative and lucidly argued post I've read on here for a while. I was going to write something about the El Nino/PDO/NAO predictions/effects myself, but it's just as well you did it for me, as you clearly have a far more comprehensive understanding of these matters than I do with my rather sketchy knowledge (though I feel slightly less sketchy now). I find it interesting that the forecast for the NAO this winter has changed so quickly from predicting a slightly positive oscillation, to predicting a negative one. Is this the sort of thing which can work as a trend, so that changing factors which have obviously led to modifications in NAO forecasts, keep changing in the same way, so that forecasts go even more negative?

I'd rather it didn't. I feel rather disillusioned with Northerlies these days! Down here in Sussex/Oxford, Northerlies aren't much use. Too many mountains in the way. And those annoying lows which don't want to come closer than denmark...grrr. Let's hope the GH slips on all the ice and ends up over scandi, bringing both of us metres of snow and ice and burst pipes...

Ah I'm getting careless. I think you're probably right. Though it certainly had a good run when it arrived. I only started posting in feb i think though, after watching previously, which i had forgotten, and from when i began posting regularly I seem to remember a greenland high in place most of the time! Thank you for the correction. As always my friend I only brought it up because predictions for this winter seem to suggest that we might see some consistent scandinavian blocking. So I feel cautiously optimistic about the chances.

A very nice post snowprincess. Beautifully written! And I would agree with you that Global Warming theory advocates (not very elegantly put...) tend to shout about it indiscriminately, often without knowing anything about it (not to suggest that you know nothing about it Dawlish). Global warming is certainly happening, but it is an extremely gradual process and neither has nor will cause such a sudden increase in temperature that snowy winters here will never be seen again. Remember also that the UK is not the entire planet. Many places exist around the globe which will have experiences opposite to ours, where their recent winters have been colder and snowier than usual. With the right synoptics, the UK will get cold, snowy weather during winter.

Well perhaps there weren't many real potent northerlies last winter, but on this forum we were certainly talking about the prospects of northerlies most of the time, and while they may not have come off to full effect every time, there was an almost ever present greeland high, and lows frequently dipped down and affected northern areas somewhat, even if not further south. Furthermore, you neglect to mention the major snowfalls up north of last march, when aberdeen and co got pounded with feet off snow. That was from a very potent and set in northerly set up. As for what you say about easterlies, I would repeat what Big bear wrote: Any incidents last winter when we experienced winds from the east, I would not call 'Easterlies'. There was no long draw from a cold pool to our east. There was no significant low pressure action near us to bring any snow, and most of the time, as you say, the scandi high was away to the east so we didnt really get a full blast. A few half hearted attempts. As you say at the end, both an easterly and a notherly depend on the right synoptic set up, and i do realise this. The reason i was being positive about the prospect of a more prominent scandi high, is that we never had a consistent, strong scandi high last winter. If we were to get that this winter, the chances of it extending west at least on one occasion and certain other factors cooperating would be reasonable.

Ah yes we're all coming back now. I've been doing the same through the summer, but i rarely contribute because summer is less interesting. If it's 25 degrees rather than 29 degrees it makes little difference, but -2 makes a big difference to +2. I can already feel the winter tension building.... As for forecasts for the coming winter, I would suggest that any forecast for scandinavian blocking is positive. From my position here in the south east, and moving slightly north west to oxford for large chunks of the coming winter, N'rlys, which we saw plenty of last winter, and even NNE'rlys, give us nothing down here. Easterlies are what we need, and what all the Uk needs if we want to see a real prolonged cold spell. Consistent scandi blocking not only encourages cold pooling to our east, but only needs to push west and south somewhat for us to have a poweful easterly. A consistent scandi high cuts out the problem of always having only one of cold pooling/easterly winds, because it brings both. As for the slightly positive NAO/El Nino forecast, if we combine that with the Scandi high, it could be good news, because the suggestions that we might have more atlantic weather this year mean we might actually get some ppn alongside the easterly wind, if atlantic lows feed in to lows over northern europe. Like in 1987: In response to Kold Weather's post, which was in response to this image I would disagree that this is a pattern we want to see. South easterly diving lows are no good, as they will bring us the worst of atlantic wet and mild(ish) weather. Lows heading north to Greenland and then dropping south towards us have been a problem throuhg the last mild ten years. We need blocking up north so that lows track on the south side of the UK. Good to be back all B)

Look this needs to be cleared up - people are getting very confused. It is really quite simple. Dawlish is right in that the research does not suggest that the Gulf Stream bringing heat north has yet slowed down. However, research does show that because of increasing levels of fresh water being released from melting ice caps in the arctic, the current running south, which is the other half of the conveyor belt, HAS been shown to be significantly weaker than when last measured, by something like 6m tonnes of water per second. Fairly substantial. This has not yet caused any noticeable drop in temperature in europe as a result of less gulf stream heat, but it has been noticed that, of the water moving north towards europe, an increasing amount is branching off earlier than "it should". This, along with the weaker current running SOUTH, has given rise to concern that a continuation of the trend, because of glbal warming, could see the gulf stream shut down altogether, very suddenly. This is based on the belief that the gulf stream won't slow down gradually to a stop, but will at some point, when there is simply not enough energy going into the cycle, or there is too much fresh water in the arctic stopping the cold water from sinking, simply stop. It's all speculation to some extent anyway, but i hope this clears up some points

Rather a lot of posts there daniel! I think a lot has been said about the gulf stream weakening though. Everybody knows about it now, at least among those interested in weather. All the research which showed that it has weakened by 30% in the last few decades was published in the papers. But, as you're clearly a bit of a scare monger, I feel i should say that not only do we have no idea of how much weakening it will take of the gulf stream to stop it, but we also don't even know whether the weakening will continue at this pace. And if it did stop, we don't know what the consequences would be exactly. And ice caps and ice sheets would be a long time coming i guarentee you. Summers wouldn't be cold enough for ice and snow to stick around, and you need a fair amount of water to make an ice sheet in the firstplace, so really, I wouldn't worry too much about that.

Here in tonbridge (the site of the big robbery yesterday!), it is snwoing moderately hard and has been increasing for almost two hours. However, we're only 30m asl here, and this place has a terrible record for collecting snow, so I'm hoping my hosue in sussex, at 150m, 500ft, will be doing better and collecting snow on the ground. It normally does well compared to places around like tonbridge. It is collecting on peoplethough here to be honest. Everyone has a fair bit collecting on them, but not on the ground or anything. I think it's probably too wet now. Its just getting wet and melted the moment it lands